(87f) Microwave Accelerated Transglycosylation of Stevioside Using Cyclodextrin Glucanotransferase

Abstract: Stevioside is a major component in commercial product with a bitter aftertaste as a natural sweetener. Aiming at producing new derivatives of stevioside for healthy products, the transglycosylation of stevioside using cyclodextrin glucanotransferase (CGTase) was investigated. Three CGTase were used in this study. The effects of reaction parameters including temperature, mass ratio of the reactants, concentration of cornstarch, enzyme loading and pH on the conversion of stevioside and the composition of the products were studied. The highest conversion of stevioside of 68.72% was obtained with a mass ratio of 1:1 ( stevioside : cornstarch), the final concentration of the cornstarch was 1%, and catalyzed by 10U CGTase /g stevioside in water at 60 ^oC for 3 hr. In addition, under same reaction conditions mentioned above, the conversion of stevioside can reach 36.25% in only 5 min with the acceleration of 80w microwave, which took 45min if conventional heating was applied.